package gr.uom.java.ast.decomposition.cfg;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;

import org.eclipse.jdt.core.dom.Block;
import org.eclipse.jdt.core.dom.BreakStatement;
import org.eclipse.jdt.core.dom.ContinueStatement;
import org.eclipse.jdt.core.dom.DoStatement;
import org.eclipse.jdt.core.dom.EnhancedForStatement;
import org.eclipse.jdt.core.dom.ForStatement;
import org.eclipse.jdt.core.dom.IfStatement;
import org.eclipse.jdt.core.dom.ReturnStatement;
import org.eclipse.jdt.core.dom.Statement;
import org.eclipse.jdt.core.dom.SwitchCase;
import org.eclipse.jdt.core.dom.SwitchStatement;
import org.eclipse.jdt.core.dom.ThrowStatement;
import org.eclipse.jdt.core.dom.WhileStatement;

import gr.uom.java.ast.MethodObject;
import gr.uom.java.ast.decomposition.AbstractStatement;
import gr.uom.java.ast.decomposition.CompositeStatementObject;
import gr.uom.java.ast.decomposition.MethodBodyObject;
import gr.uom.java.ast.decomposition.StatementObject;
import gr.uom.java.ast.decomposition.TryStatementObject;

public class CFG extends Graph {
	private static final int PUSH_NEW_LIST = 0;
	private static final int JOIN_TOP_LIST = 1;
	private static final int PLACE_NEW_LIST_SECOND_FROM_TOP = 2;
	private static final int JOIN_SECOND_FROM_TOP_LIST = 3;
	private MethodObject method;
	private Stack<List<CFGBranchConditionalNode>> unjoinedConditionalNodes;
	private Map<CFGBranchSwitchNode, List<CFGNode>> switchBreakMap;
	private Map<CFGTryNode, List<CFGNode>> directlyNestedNodesInTryBlocks;
	private BasicBlockCFG basicBlockCFG;
	
	public CFG(MethodObject method) {
		this.method = method;
		this.unjoinedConditionalNodes = new Stack<List<CFGBranchConditionalNode>>();
		this.switchBreakMap = new LinkedHashMap<CFGBranchSwitchNode, List<CFGNode>>();
		this.directlyNestedNodesInTryBlocks = new LinkedHashMap<CFGTryNode, List<CFGNode>>();
		MethodBodyObject methodBody = method.getMethodBody();
		if(methodBody != null) {
			CompositeStatementObject composite = methodBody.getCompositeStatement();
			process(new ArrayList<CFGNode>(), composite);
			GraphNode.resetNodeNum();
			this.basicBlockCFG = new BasicBlockCFG(this);
		}
	}

	public MethodObject getMethod() {
		return method;
	}

	public BasicBlockCFG getBasicBlockCFG() {
		return basicBlockCFG;
	}

	public List<BasicBlock> getBasicBlocks() {
		return basicBlockCFG.getBasicBlocks();
	}

	public Map<CFGTryNode, List<CFGNode>> getDirectlyNestedNodesInTryBlocks() {
		return directlyNestedNodesInTryBlocks;
	}

	private List<CFGNode> process(List<CFGNode> previousNodes, CompositeStatementObject composite) {
		if(composite instanceof TryStatementObject) {
			AbstractStatement firstStatement = composite.getStatements().get(0);
			composite = (CompositeStatementObject)firstStatement;
		}
		int i = 0;
		for(AbstractStatement abstractStatement : composite.getStatements()) {
			if(abstractStatement instanceof StatementObject) {
				StatementObject statement = (StatementObject)abstractStatement;
				previousNodes = processNonCompositeStatement(previousNodes, statement, composite);
			}
			else if(abstractStatement instanceof CompositeStatementObject) {
				CompositeStatementObject compositeStatement = (CompositeStatementObject)abstractStatement;
				if(compositeStatement.getStatement() instanceof Block) {
					previousNodes = process(previousNodes, compositeStatement);
				}
				else if(compositeStatement instanceof TryStatementObject) {
					TryStatementObject tryStatement = (TryStatementObject)compositeStatement;
					if(!tryStatement.hasResources()) {
						//if a try node does not have resources, it is treated as a block and is omitted
						CFGTryNode tryNode = new CFGTryNode(compositeStatement);
						//nodes.add(tryNode);
						directlyNestedNodeInTryBlock(tryNode);
						directlyNestedNodesInTryBlocks.put(tryNode, new ArrayList<CFGNode>());
						AbstractStatement firstStatement = compositeStatement.getStatements().get(0);
						previousNodes = process(previousNodes, (CompositeStatementObject)firstStatement);
					}
					else {
						//if a try node has resources, it is treated as a non-composite node
						CFGTryNode tryNode = new CFGTryNode(compositeStatement);
						directlyNestedNodeInTryBlock(tryNode);
						nodes.add(tryNode);
						directlyNestedNodesInTryBlocks.put(tryNode, new ArrayList<CFGNode>());
						createTopDownFlow(previousNodes, tryNode);
						ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
						currentNodes.add(tryNode);
						previousNodes = currentNodes;
						AbstractStatement firstStatement = compositeStatement.getStatements().get(0);
						previousNodes = process(previousNodes, (CompositeStatementObject)firstStatement);
					}
				}
				else if(isLoop(compositeStatement)) {
					previousNodes = processLoopStatement(previousNodes, compositeStatement);
				}
				else if(compositeStatement.getStatement() instanceof DoStatement) {
					previousNodes = processDoStatement(previousNodes, compositeStatement);
				}
				else if(compositeStatement.getStatement() instanceof SwitchStatement) {
					int action = getAction(composite, i, compositeStatement);
					previousNodes = processSwitchStatement(previousNodes, compositeStatement, action);
				}
				else if(compositeStatement.getStatement() instanceof IfStatement) {
					int action = getAction(composite, i, compositeStatement);
					previousNodes = processIfStatement(previousNodes, compositeStatement, action);
				}
			}
			i++;
		}
		return previousNodes;
	}

	private List<CFGNode> processDoStatement(List<CFGNode> previousNodes, CompositeStatementObject compositeStatement) {
		List<CFGNode> tmpNodes = previousNodes;
		previousNodes = process(previousNodes, compositeStatement);
		CFGBranchNode currentNode = new CFGBranchDoLoopNode(compositeStatement);
		nodes.add(currentNode);
		directlyNestedNodeInTryBlock(currentNode);
		createTopDownFlow(previousNodes, currentNode);
		CFGNode topNode = getCommonNextNode(tmpNodes);
		if(topNode == null)
			topNode = (CFGNode)nodes.toArray()[0];
		Flow flow = new Flow(currentNode, topNode);
		flow.setTrueControlFlow(true);
		flow.setLoopbackFlow(true);
		edges.add(flow);
		ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
		currentNodes.add(currentNode);
		previousNodes = currentNodes;
		return previousNodes;
	}

	private List<CFGNode> processLoopStatement(List<CFGNode> previousNodes, CompositeStatementObject compositeStatement) {
		CFGBranchNode currentNode = new CFGBranchLoopNode(compositeStatement);
		nodes.add(currentNode);
		directlyNestedNodeInTryBlock(currentNode);
		createTopDownFlow(previousNodes, currentNode);
		previousNodes = new ArrayList<CFGNode>();
		ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
		currentNodes.add(currentNode);
		previousNodes.addAll(process(currentNodes, compositeStatement));
		for(CFGNode previousNode : previousNodes) {
			Flow flow = new Flow(previousNode, currentNode);
			if(previousNode instanceof CFGBranchNode) {
				if(previousNode.equals(currentNode))
					flow.setTrueControlFlow(true);
				else
					flow.setFalseControlFlow(true);
			}
			flow.setLoopbackFlow(true);
			edges.add(flow);
		}
		if(previousNodes.size() > 1) {
			List<CFGBranchConditionalNode> conditionalNodes = unjoinedConditionalNodes.pop();
			for(CFGBranchConditionalNode conditionalNode : conditionalNodes) {
				conditionalNode.setJoinNode(currentNode);
			}
		}
		previousNodes = currentNodes;
		return previousNodes;
	}

	private int getAction(CompositeStatementObject parentComposite, int i, CompositeStatementObject childComposite) {
		int action = PUSH_NEW_LIST;
		List<AbstractStatement> statements = new ArrayList<AbstractStatement>(parentComposite.getStatements());
		CompositeStatementObject parent = statements.get(0).getParent();
		boolean isBlockWithoutCompositeParent = isBlockWithoutCompositeParent(parent);
		if(parent.getStatement() instanceof Block)
			parent = parent.getParent();
		int position = i;
		while(parent != null && parent instanceof TryStatementObject) {
			CompositeStatementObject tryStatement = parent;
			CompositeStatementObject tryStatementParent = tryStatement.getParent();
			List<AbstractStatement> tryParentStatements = new ArrayList<AbstractStatement>(tryStatementParent.getStatements());
			if(tryStatementParent.getStatement() instanceof Block)
				tryStatementParent = tryStatementParent.getParent();
			int positionOfTryStatementInParent = 0;
			int j = 0;
			for(AbstractStatement statement : tryParentStatements) {
				if(statement.equals(tryStatement)) {
					positionOfTryStatementInParent = j;
					break;
				}
				j++;
			}
			if(((TryStatementObject)tryStatement).hasResources()) {
				tryParentStatements.addAll(positionOfTryStatementInParent + 1, statements);
			}
			else {
				tryParentStatements.remove(tryStatement);
				tryParentStatements.addAll(positionOfTryStatementInParent, statements);
			}
			statements = tryParentStatements;
			parent = tryStatementParent;
			if(((TryStatementObject)tryStatement).hasResources())
				position = positionOfTryStatementInParent + position + 1;
			else
				position = positionOfTryStatementInParent + position;
		}
		if(parent != null && parent.getStatement() instanceof SwitchStatement &&
				parentComposite.getStatement() instanceof Block) {
			List<AbstractStatement> switchStatements = new ArrayList<AbstractStatement>(parent.getStatements());
			int positionOfBlockInParentSwitch = 0;
			int j = 0;
			for(AbstractStatement statement : switchStatements) {
				if(statement.equals(parentComposite)) {
					positionOfBlockInParentSwitch = j;
					break;
				}
				j++;
			}
			switchStatements.remove(parentComposite);
			switchStatements.addAll(positionOfBlockInParentSwitch, statements);
			statements = switchStatements;
			position = positionOfBlockInParentSwitch + position;
		}
		if(parent != null && isBlockWithoutCompositeParent) {
			List<AbstractStatement> blockStatements = new ArrayList<AbstractStatement>(parent.getStatements());
			int positionOfBlockInParent = 0;
			int j = 0;
			for(AbstractStatement statement : blockStatements) {
				if(statement.equals(parentComposite)) {
					positionOfBlockInParent = j;
					break;
				}
				j++;
			}
			blockStatements.remove(parentComposite);
			blockStatements.addAll(positionOfBlockInParent, statements);
			statements = blockStatements;
			position = positionOfBlockInParent + position;
		}
		if(statements.size() == 1) {
			action = JOIN_TOP_LIST;
			if(parent != null) {
				if(isLoop(parent))
					action = PUSH_NEW_LIST;
				else if(parent.getStatement() instanceof DoStatement)
					action = PLACE_NEW_LIST_SECOND_FROM_TOP;
			}
		}
		else if(statements.size() > 1) {
			AbstractStatement previousStatement = null;
			if(position >= 1)
				previousStatement = statements.get(position-1);
			int j = 0;
			while(previousStatement != null && previousStatement instanceof TryStatementObject && !((TryStatementObject)previousStatement).hasResources()) {
				CompositeStatementObject tryStatement = (CompositeStatementObject)previousStatement;
				AbstractStatement firstStatement = tryStatement.getStatements().get(0);
				if(firstStatement instanceof CompositeStatementObject) {
					CompositeStatementObject tryBlock = (CompositeStatementObject)firstStatement;
					List<AbstractStatement> tryBlockStatements = tryBlock.getStatements();
					if(tryBlockStatements.size() > 0) {
						//previous statement is the last statement of this try block
						previousStatement = tryBlockStatements.get(tryBlockStatements.size()-1);
					}
					else {
						//try block is empty and previous statement is the statement before this try block
						if(position >= 2+j)
							previousStatement = statements.get(position-2-j);
						else
							previousStatement = null;
					}
				}
				j++;
			}
			while(previousStatement != null && isBlockWithoutCompositeParent(previousStatement)) {
				CompositeStatementObject block = (CompositeStatementObject)previousStatement;
				List<AbstractStatement> blockStatements = block.getStatements();
				if(blockStatements.size() > 0) {
					//previous statement is the last statement of this block
					previousStatement = blockStatements.get(blockStatements.size()-1);
				}
			}
			if(statements.get(statements.size()-1).equals(childComposite)) {
				//current if statement is the last statement of the composite statement
				if(previousStatement != null && previousStatement.getStatement() instanceof IfStatement) {
					action = JOIN_SECOND_FROM_TOP_LIST;
					if(parent != null && (isLoop(parent) || parent.getStatement() instanceof DoStatement))
						action = PLACE_NEW_LIST_SECOND_FROM_TOP;
				}
				else {
					action = JOIN_TOP_LIST;
					if(parent != null && (isLoop(parent) || parent.getStatement() instanceof DoStatement))
						action = PUSH_NEW_LIST;
				}
			}
			else {
				if(previousStatement != null && previousStatement.getStatement() instanceof IfStatement)
					action = PLACE_NEW_LIST_SECOND_FROM_TOP;
				else {
					action = PUSH_NEW_LIST;
					if(parent != null && parent.getStatement() instanceof DoStatement &&
							statements.get(0).getStatement() instanceof IfStatement)
						action = PLACE_NEW_LIST_SECOND_FROM_TOP;
				}
			}
		}
		return action;
	}

	private boolean isBlockWithoutCompositeParent(AbstractStatement statement) {
		boolean isBlock = false;
		if(statement.getStatement() instanceof Block) {
			isBlock = true;
		}
		boolean parentIsBlock = false;
		AbstractStatement parent = (AbstractStatement)statement.getParent();
		if(parent != null && parent.getStatement() instanceof Block) {
			parentIsBlock = true;
		}
		return isBlock && parentIsBlock;
	}

	private List<CFGNode> processNonCompositeStatement(List<CFGNode> previousNodes, StatementObject statement,
			CompositeStatementObject composite) {
		//special handling of break, continue, return
		CFGNode currentNode = createNonCompositeNode(statement);
		nodes.add(currentNode);
		if((currentNode instanceof CFGBreakNode || currentNode instanceof CFGExitNode) &&
				composite.getStatement() instanceof SwitchStatement && directlyNestedNode(currentNode, composite)) {
			CFGBranchSwitchNode switchNode = getMostRecentSwitchNode();
			if(switchBreakMap.containsKey(switchNode)) {
				List<CFGNode> breakList = switchBreakMap.get(switchNode);
				breakList.add(currentNode);
			}
			else {
				List<CFGNode> breakList = new ArrayList<CFGNode>();
				breakList.add(currentNode);
				switchBreakMap.put(switchNode, breakList);
			}
			createTopDownFlow(previousNodes, currentNode);
		}
		else if(currentNode instanceof CFGSwitchCaseNode) {
			CFGSwitchCaseNode switchCase = (CFGSwitchCaseNode)currentNode;
			if(previousNodesContainBreakOrReturn(previousNodes, composite)) {
				CFGBranchSwitchNode switchNode = getMostRecentSwitchNode();
				Flow flow = new Flow(switchNode, currentNode);
				if(switchCase.isDefault())
					flow.setFalseControlFlow(true);
				else
					flow.setTrueControlFlow(true);
				edges.add(flow);
			}
			else
				createTopDownFlow(previousNodes, currentNode);
		}
		else
			createTopDownFlow(previousNodes, currentNode);
		ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
		currentNodes.add(currentNode);
		previousNodes = currentNodes;
		return previousNodes;
	}

	private CFGNode createNonCompositeNode(StatementObject statement) {
		CFGNode currentNode;
		Statement astStatement = statement.getStatement();
		if(astStatement instanceof ReturnStatement)
			currentNode = new CFGExitNode(statement);
		else if(astStatement instanceof SwitchCase)
			currentNode = new CFGSwitchCaseNode(statement);
		else if(astStatement instanceof BreakStatement)
			currentNode = new CFGBreakNode(statement);
		else if(astStatement instanceof ContinueStatement)
			currentNode = new CFGContinueNode(statement);
		else if(astStatement instanceof ThrowStatement)
			currentNode = new CFGThrowNode(statement);
		else
			currentNode = new CFGNode(statement);
		directlyNestedNodeInTryBlock(currentNode);
		return currentNode;
	}

	private boolean previousNodesContainBreakOrReturn(List<CFGNode> previousNodes, CompositeStatementObject composite) {
		for(CFGNode previousNode : previousNodes) {
			Statement statement = previousNode.getASTStatement();
			if((statement instanceof BreakStatement || statement instanceof ReturnStatement) &&
					directlyNestedNode(previousNode, composite))
				return true;
		}
		return false;
	}

	private boolean directlyNestedNode(CFGNode node, CompositeStatementObject composite) {
		for(AbstractStatement statement : composite.getStatements()) {
			if(statement.equals(node.getStatement()))
				return true;
			if(statement instanceof CompositeStatementObject) {
				CompositeStatementObject composite2 = (CompositeStatementObject)statement;
				Statement astComposite2 = composite2.getStatement();
				if(astComposite2 instanceof Block) {
					if(directlyNestedNode(node, composite2))
						return true;
				}
			}
		}
		return false;
	}

	private void directlyNestedNodeInTryBlock(CFGNode node) {
		for(CFGTryNode tryNode : directlyNestedNodesInTryBlocks.keySet()) {
			if(directlyNestedNode(node, (TryStatementObject)tryNode.getStatement())) {
				List<CFGNode> directlyNestedNodes = directlyNestedNodesInTryBlocks.get(tryNode);
				directlyNestedNodes.add(node);
				break;
			}
		}
	}

	private List<CFGNode> processSwitchStatement(List<CFGNode> previousNodes, CompositeStatementObject compositeStatement, int action) {
		CFGBranchSwitchNode currentNode = new CFGBranchSwitchNode(compositeStatement);
		handleAction(currentNode, action);
		nodes.add(currentNode);
		directlyNestedNodeInTryBlock(currentNode);
		createTopDownFlow(previousNodes, currentNode);
		previousNodes = new ArrayList<CFGNode>();
		ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
		currentNodes.add(currentNode);
		previousNodes.addAll(process(currentNodes, compositeStatement));
		List<CFGNode> breakList = switchBreakMap.get(currentNode);
		if(breakList != null) {
			for(CFGNode node : breakList) {
				if(!previousNodes.contains(node))
					previousNodes.add(node);
			}
		}
		if(currentNode.getFalseControlFlow() == null)
			previousNodes.add(currentNode);
		return previousNodes;
	}

	private List<CFGNode> processIfStatement(List<CFGNode> previousNodes, CompositeStatementObject compositeStatement, int action) {
		CFGBranchIfNode currentNode = new CFGBranchIfNode(compositeStatement);
		handleAction(currentNode, action);
		
		nodes.add(currentNode);
		directlyNestedNodeInTryBlock(currentNode);
		createTopDownFlow(previousNodes, currentNode);
		previousNodes = new ArrayList<CFGNode>();
		List<AbstractStatement> ifStatementList = compositeStatement.getStatements();
		AbstractStatement thenClause = ifStatementList.get(0);
		if(thenClause instanceof StatementObject) {
			StatementObject thenClauseStatement = (StatementObject)thenClause;
			CFGNode thenClauseNode = createNonCompositeNode(thenClauseStatement);
			nodes.add(thenClauseNode);
			ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
			currentNodes.add(currentNode);
			createTopDownFlow(currentNodes, thenClauseNode);
			previousNodes.add(thenClauseNode);
		}
		else if(thenClause instanceof CompositeStatementObject) {
			CompositeStatementObject thenClauseCompositeStatement = (CompositeStatementObject)thenClause;
			ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
			currentNodes.add(currentNode);
			if(thenClauseCompositeStatement.getStatement() instanceof IfStatement)
				previousNodes.addAll(processIfStatement(currentNodes, thenClauseCompositeStatement, JOIN_TOP_LIST));
			else if(thenClauseCompositeStatement.getStatement() instanceof SwitchStatement)
				previousNodes.addAll(processSwitchStatement(currentNodes, thenClauseCompositeStatement, JOIN_TOP_LIST));
			else if(isLoop(thenClauseCompositeStatement))
				previousNodes.addAll(processLoopStatement(currentNodes, thenClauseCompositeStatement));
			else if(thenClauseCompositeStatement.getStatement() instanceof DoStatement)
				previousNodes.addAll(processDoStatement(currentNodes, thenClauseCompositeStatement));
			else
				previousNodes.addAll(process(currentNodes, thenClauseCompositeStatement));
		}
		if(ifStatementList.size() == 2) {
			AbstractStatement elseClause = ifStatementList.get(1);
			if(elseClause instanceof StatementObject) {
				StatementObject elseClauseStatement = (StatementObject)elseClause;
				CFGNode elseClauseNode = createNonCompositeNode(elseClauseStatement);
				nodes.add(elseClauseNode);
				ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
				currentNodes.add(currentNode);
				createTopDownFlow(currentNodes, elseClauseNode);
				previousNodes.add(elseClauseNode);
			}
			else if(elseClause instanceof CompositeStatementObject) {
				CompositeStatementObject elseClauseCompositeStatement = (CompositeStatementObject)elseClause;
				ArrayList<CFGNode> currentNodes = new ArrayList<CFGNode>();
				currentNodes.add(currentNode);
				if(elseClauseCompositeStatement.getStatement() instanceof IfStatement)
					previousNodes.addAll(processIfStatement(currentNodes, elseClauseCompositeStatement, JOIN_TOP_LIST));
				else if(elseClauseCompositeStatement.getStatement() instanceof SwitchStatement)
					previousNodes.addAll(processSwitchStatement(currentNodes, elseClauseCompositeStatement, JOIN_TOP_LIST));
				else if(isLoop(elseClauseCompositeStatement))
					previousNodes.addAll(processLoopStatement(currentNodes, elseClauseCompositeStatement));
				else if(elseClauseCompositeStatement.getStatement() instanceof DoStatement)
					previousNodes.addAll(processDoStatement(currentNodes, elseClauseCompositeStatement));
				else
					previousNodes.addAll(process(currentNodes, elseClauseCompositeStatement));
			}
		}
		else {
			previousNodes.add(currentNode);
		}
		return previousNodes;
	}

	private void handleAction(CFGBranchConditionalNode currentNode, int action) {
		if(action == JOIN_TOP_LIST && !unjoinedConditionalNodes.empty()) {
			List<CFGBranchConditionalNode> topList = unjoinedConditionalNodes.peek();
			topList.add(currentNode);
		}
		else if(action == JOIN_SECOND_FROM_TOP_LIST) {
			if(unjoinedConditionalNodes.size() > 1) {
				List<CFGBranchConditionalNode> list = unjoinedConditionalNodes.elementAt(unjoinedConditionalNodes.size()-2);
				list.add(currentNode);
			}
			else {
				List<CFGBranchConditionalNode> topList = unjoinedConditionalNodes.pop();
				List<CFGBranchConditionalNode> list = new ArrayList<CFGBranchConditionalNode>();
				list.add(currentNode);
				unjoinedConditionalNodes.push(list);
				unjoinedConditionalNodes.push(topList);
			}
		}
		else if(action == PLACE_NEW_LIST_SECOND_FROM_TOP && !unjoinedConditionalNodes.empty()) {
			List<CFGBranchConditionalNode> topList = unjoinedConditionalNodes.pop();
			List<CFGBranchConditionalNode> list = new ArrayList<CFGBranchConditionalNode>();
			list.add(currentNode);
			unjoinedConditionalNodes.push(list);
			unjoinedConditionalNodes.push(topList);
		}
		else {
			List<CFGBranchConditionalNode> list = new ArrayList<CFGBranchConditionalNode>();
			list.add(currentNode);
			unjoinedConditionalNodes.push(list);
		}
	}

	private void createTopDownFlow(List<CFGNode> previousNodes, CFGNode currentNode) {
		for(CFGNode previousNode : previousNodes) {
			Flow flow = new Flow(previousNode, currentNode);
			int numberOfImmediateTryBlocks = getNumberOfImmediateTryBlocks(currentNode);
			if(previousNode instanceof CFGBranchNode) {
				if(currentNode.getId() == previousNode.getId() + 1 + numberOfImmediateTryBlocks &&
						!(previousNode instanceof CFGBranchDoLoopNode))
					flow.setTrueControlFlow(true);
				else
					flow.setFalseControlFlow(true);
			}
			edges.add(flow);
		}
		if(previousNodes.size() > 1) {
			List<CFGBranchConditionalNode> conditionalNodes = unjoinedConditionalNodes.pop();
			for(CFGBranchConditionalNode conditionalNode : conditionalNodes) {
				conditionalNode.setJoinNode(currentNode);
			}
		}
	}

	private int getNumberOfImmediateTryBlocks(CFGNode node) {
		for(CFGTryNode tryNode : directlyNestedNodesInTryBlocks.keySet()) {
			List<CFGNode> directlyNestedNodes = directlyNestedNodesInTryBlocks.get(tryNode);
			if(directlyNestedNodes.contains(node))
				return 1 + getNumberOfImmediateTryBlocks(tryNode);
		}
		return 0;
	}

	private boolean isLoop(CompositeStatementObject compositeStatement) {
		if(compositeStatement.getStatement() instanceof WhileStatement ||
				compositeStatement.getStatement() instanceof ForStatement ||
				compositeStatement.getStatement() instanceof EnhancedForStatement)
			return true;
		return false;
	}

	private CFGNode getCommonNextNode(List<CFGNode> nodes) {
		HashMap<CFGNode, Integer> nextNodeCounterMap = new HashMap<CFGNode, Integer>();
		for(CFGNode node : nodes) {
			for(GraphEdge edge : node.outgoingEdges) {
				CFGNode nextNode = (CFGNode)edge.dst;
				if(nextNodeCounterMap.containsKey(nextNode))
					nextNodeCounterMap.put(nextNode, nextNodeCounterMap.get(nextNode)+1);
				else
					nextNodeCounterMap.put(nextNode, 1);
			}
		}
		for(CFGNode key : nextNodeCounterMap.keySet()) {
			if(nextNodeCounterMap.get(key) == nodes.size())
				return key;
		}
		return null;
	}

	private CFGBranchSwitchNode getMostRecentSwitchNode() {
		for(int i=unjoinedConditionalNodes.size()-1; i>=0; i--) {
			List<CFGBranchConditionalNode> unjoinedConditionalNodeList = unjoinedConditionalNodes.get(i);
			for(int j=unjoinedConditionalNodeList.size()-1; j>=0; j--) {
				CFGBranchConditionalNode conditionalNode = unjoinedConditionalNodeList.get(j);
				if(conditionalNode instanceof CFGBranchSwitchNode) {
					return (CFGBranchSwitchNode)conditionalNode;
				}
			}
		}
		return null;
	}
}
